The present invention relates to a process for producing an allyl sulfone derivative which is a starting material for vitamin A derivatives and various terpene compounds to be used for medicament, feed additives, food additives, etc., and an intermediate for producing it.
As a process for producing a vitamin A derivative, there has been known a process using an intermediate compound obtained by reacting a halogen compound, which is derived from a C10 alcohol compound such as linalool, geraniol, or the like by a reaction step using an expensive Pd catalyst and a ligand, with a C10 sulfone (a compound represented by the formula (7) described below) to introduce a C10 side chain (EP 900785 A).
According to the process of the present invention, an allyl sulfone derivative represented by the formula (3) described below which is useful as an intermediate for producing vitamin A derivatives and the like, can be industrially and advantageously produced from a halide compound (a compound represented by the formula (8) described below) without requiring an expensive Pd catalyst and a ligand, thereby requiring no recovery step thereof.
That is, the present invention provides:
1. An allyl halide derivative represented by the formula (1): 
wherein Ar is an optionally substituted aryl group, X is a halogen atom, and the corrugated line means either one of E/Z geometrical isomers or a mixture thereof;
2. A process for producing an allyl sulfone derivative represented by the formula (3): 
wherein Ar and the corrugated line are as defined above, which comprises reacting an aryl sulfinic acid or a salt thereof, represented by the formula (2):
ArSO2Mxe2x80x83xe2x80x83(2)
wherein Ar is as defined above, and M is hydrogen atom, sodium atom or potassium atom, with an allyl halide derivative represented by the formula (1): 
wherein Ar, X and the corrugated line are as defined above; and
3. A process for producing the above allyl halide represented by the formula (1) which comprises subjecting an allyl alcohol derivative represented by the formula (5): 
wherein Ar and the corrugated line are as defined above, to a halogenation reaction.
Detailed explanation of the present invention will be set forth hereinafter.
Ar of the compounds represented by respective formulas in the present invention is an optionally substituted aryl group. Examples of the aryl group include phenyl group, naphthyl group, and the like, and examples of the substituent thereof include a C1 to C5 straight or branched chain alkyl group (e.g., methyl, ethyl, propyl, isopropyl, butyl, pentyl, etc.), a C1 to C5 straight or branched chain alkoxy group (methoxy, ethoxy, propoxy, isopropoxy, butoxy, pentyloxy, etc.), a halogen atom (fluorine, chlorine, bromine, iodine), nitro group, and the like. Specifically, there are phenyl, naphthyl, o-tolyl, m-tolyl, p-tolyl, o-methoxyphenyl, m-methoxyphenyl, p-methoxyphenyl, o-chlorophenyl, m-chlorophenyl, p-chlorophenyl, o-bromophenyl, m-bromophenyl, p-bromophenyl, o-iodophenyl, m-iodophenyl, p-iodophenyl, o-fluorophenyl, m-fluorophenyl, p-fluorophenyl, o-nitrophenyl, m-nitrophenyl, p-nitrophenyl, and the like.
Further, the substituent X represents a halogen atom and, specifically, there are chlorine atom, bromine atom and iodine atom.
In the present invention, the allyl halide derivative (1) can be produced by reacting a halogenation agent with the allyl alcohol derivative of the above formula (5).
The halogenation agent is not specifically limited and, for example, reactive halides such as a group 4 transition metal halide, a sulfur, phosphorus or boron halide, an acid chloride, and the like can be exemplified. These halogenation agents can be reacted in the presence of a formamide compound. Of course, the halogenation reaction can be carried out in the presence of a Vilsmeyer complex formed by the above halogenation agent and a formamide compound.
As to respective halogenation agents, more detailed explanation will be set forth hereinafter.
Examples of the group 4 transition metal halide include titanium tetrachloride, titanium tetrabromide, titanium tetraiodide, dichlorotitanium diisopropoxide, chlorotitanium triisopropoxide, zirconium tetrachloride, zirconium tetrabromide, zirconium tetraiodide, hafnium tetrachloride, hafnium tetrabromide, hafnium tetraiodide, and the like. Usually, the amount thereof to be used is about 0.3 to 5 mole, preferably about 1 to 3 mole per 1 mole of the ally alcohol derivative (5). Usually, a solvent is used for this reaction. Examples of such solvent include ether solvents such as diethyl ether, tetrahydrofuran, 1,4-dioxane, dimethoxyethane, anisole, etc.; hydrocarbon solvents such as n-hexane, cyclohexane, n-pentane, benzene, toluene, xylene, etc.; halogenated hydrocarbon solvents such as chloroform, dichloromethane, 1,2-dichloroethane, monochlorobenzene, o-dichlorobenzene, etc.; ketone solvents such as acetone, methyl ethyl ketone., methyl isobutyl ketone, acetylacetone, etc.; or aprotic polar solvents such as acetonitrile, N,N-dimethylformamide, dimethyl sulfoxide, N,N-dimethylacetamide, hexamethylphosphoric triamide, etc. They may be used alone or in the form of a mixed solvent of two or more thereof.
Preferably, the above halogenation reaction is carried out, for example, in the presence a coordination compound such as an ether compound inclusive the above ether solvent or a ketone compound inclusive the above ketone solvent. They may be used alone or in the form of a mixture of two or more thereof.
Examples of the coordination compound include C2 to C10 straight or branched ether compounds and ketone compounds. Specifically, as the ether compounds, there are dimethyl ether, methyl ethyl ether, diethyl ether, methyl t-butyl ether, methyl cellosolve, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, tetrahydrofuran, 1,4-dioxane, and the like; and as the ketone compounds, there are acetone, diethyl ketone, methyl ethyl ketone, methyl isobutyl ketone, methyl t-butyl ketone, cyclopentenone, cyclohexanone, and the like.
The amount of the coordination compound to be used may be that sufficient to serve as a solvent regardless of a halogenation agent to be used and the addition of about 5 mole thereof per 1 mole of the allyl alcohol derivative (5) is sufficient. Usually, the reaction temperature can be freely selected within the range of xe2x88x9278xc2x0 C. to the boiling point of a solvent but, preferably, within the range of about xe2x88x9220 to 80xc2x0 C.
Examples of the sulfur, phosphorus or boron halide and the acid chloride include thionyl chloride, thionyl bromide, phosphorus trichloride, phosphorus pentachloride, phosphorus oxytrichloride, phosphorus tribromide, phosphorus pentabromide, phosphorus triiodie, boron trichloride, boron tribromide, boron triiodie, phosgene, oxalyl chloride, and the like. Usually, the amount thereof to be used is about 0.3 to 5 moles, preferably, about 1 to 3 moles per 1 mole of the allyl alcohol derivative (5).
Usually, a solvent is used for this reaction. Examples of such solvent include ether solvents such as diethyl ether, tetrahydrofuran, 1,4-dioxane, dimethoxyethane, anisole, etc.; hydrocarbon solvents such as n-hexane, cyclohexane, n-pentane, benzene, toluene, xylene, etc.; halogenated hydrocarbon solvents such as chloroform, dichloromethane, 1,2-dichloroethane, monochlorobenzene, o-dichlorobenzene, etc.; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, acetylacetone, etc.; or aprotic polar solvents such as acetonitrile, N,N-dimethylformamide, dimethyl sulfoxide, N,N-dimethylacetamide, hexamethylphosphoric triamide, etc. The reaction temperature can be freely selected within the range of xe2x88x9278xc2x0 C. to the boiling point of a solvent but, preferably, within the range of about xe2x88x9220 to 80xc2x0 C.
A Vilsmeyer complex can be formed by coexisting a halogenation agent such as thionyl chloride, thionyl bromide, phosphorus trichloride, phosphorus pentachloride, phosphorus oxytrichloride, phosphorus tribromide, phosphorus pentabromide, phosphorus triiodie, boron trichloride, boron tribromide, boron triiodie, phosgene, oxalyl chloride, or the like with a formamide compound to carry out the halogenation reaction. As the formamide compound to be used together with these halogenation agents, there are N,N-dimethylformamide, N-methylformamide, formamide, N-methylformanilide, and the like. Usually, the amount of the halogenation agent to be used is about 0.3 to 5 moles, preferably about 0.5 to 3 moles per 1 mole of the allyl alcohol derivative (5). Further, usually, the amount of the formamide compound to be used is about 0.3 to 5 moles, preferably about 0.5 to 3 moles per 1 mole of the allyl alcohol derivative (5).
Usually, a solvent is used for this reaction. Examples of such solvent include ether solvents such as diethyl ether, tetrahydrofuran, 1,4-dioxane, dimethoxyethane, anisole, etc.; hydrocarbon solvents such as n-hexane, cyclohexane, n-pentane, benzene, toluene, xylene, etc.; halogenated hydrocarbon solvents such as chloroform, dichloromethane, 1,2-dichloroethane, monochlorobenzene, o-dichlorobenzene, etc.; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, acetylacetone, etc.; and aprotic polar solvents such as acetonitrile, N,N-dimethylformamide, dimethyl sulfoxide, N,N-dimethylacetamide, hexamethylphosphoric triamide, etc. The reaction temperature can be freely selected within the range of xe2x88x9278xc2x0 C. to the boiling point of a solvent but, preferably, within the range of about xe2x88x9220 to 50xc2x0 C.
After the reaction, the allyl halide derivative (1) can be obtained by carrying out a conventional work up procedure. If necessary, it can be purified by extraction, washing, various kinds of chromatography, and the like.
The ally sulfinic acid represented by the formula (2) or a salt thereof can be obtained by reducing an aryl sulfonyl chloride represented by the formula (4):
ArSO2Clxe2x80x83xe2x80x83(4)
wherein Ar is an optionally substituted aryl group. Preferably, this reduction reaction is carried out in the presence of a reducing agent and a base in water. As the reducing agent, a sulfite or a bisulfite is preferred and, specifically, there are, for example, sodium sulfite, potassium sulfite, sodium bisulfite, potassium bisulfite and the like. Usually, the amount thereof to be used is within the range of about 1 to 2.5 moles, preferably about 1 to 2 moles per 1 mole of the aryl sulfonyl chloride (4). As the base to be present together with the reducing agent, preferred are an alkali metal hydroxide, an alkali metal carbonate, an alkali metal bicarbonate, and the like. Specifically, examples thereof include sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, and the like. Usually, the amount thereof to be used is within the range of about 1 to 5 moles, preferably about 1 to 2.5 moles per 1 mole of the aryl sulfonyl chloride (4) and the reaction temperature is, usually, within the range of 0 to 100xc2x0 C., preferably within the range of about 20 to 70xc2x0 C.
After completion of the reaction, the aryl sulfinic acid or a salt thereof obtained can be isolated. Alternatively, the ally sulfone derivative (3) can be obtained from the aryl sulfonyl chloride by one-pot operation without isolation of thus-produced aryl sulfinic acid or a salt thereof by addition of the allyl halide derivative (1) to the reaction mixture. Usually, the amount of the ally halide derivative (1) to be added is within the range of about 0.3 to 1.2 moles, preferably about 0.7 to 1 moles per 1 mole of the aryl sulfonyl chloride (4).
It is preferable to carry out the above reaction in a biphasic system consisting of water and a hydrophobic organic solvent in the presence of a phase-transfer catalyst. Examples of the hydrophobic organic solvent to be used include hydrocarbon solvents such as n-hexane, n-heptane, cyclohexane, benzene, toluene, xylene, etc.; halogenated hydrocarbon solvents such as 1-chlorobutane, 1,2-dichloroethane, chlorobenzene, o-dichlorobenzene, trifluoromethylbenezene, etc.; ketone solvents such as acetone, methyl isobutyl ketone, etc.; ester solvents such as methyl acetate, ethyl acetate, etc.; amide solvents such as N,N-dimethylformamide, etc.; and ether solvents such as methyl t-butyl ether, etc.
Examples of the phase-transfer catalyst to be used include a quaternary ammonium salt, a quaternary phosphonium salt, a sulfonium salt, etc. As the quaternary ammonium salt, there are, for example, tetramethylammonium chloride, tetraethylammonium chloride, tetrapropylammonium chloride, tetrabutylammonium chloride, tetraoctylammonium chloride, tetrahexadecylammonium chloride, tetraoctadecylammonium chloride, benzyltrimethylammonium chloride, benzyltriethylammonium chloride, benzyltributylammonium chloride, 1-methylpyridinium chloride, 1-hexadecylpyridinium chloride, 1,4-dimethylpyridinium chloride, tetramethyl-2-butylammonium chloride, trimethylcyclopropylammonium chloride, tetramethylammonium bromide, tetraethylammonium bromide, tetrapropylammonium bromide, tetrabutylammonium bromide, tetraoctylammonium bromide, tetrahexadecylammonium bromide, tetraoctadecylammonium bromide, benzyltrimethylammonium bromide, benzyltriethylammonium bromide, benzyltributylammonium bromide, 1-methylpyridinium bromide, 1-hexadecylpyridinium bromide, 1,4-dimethylpyridinium bromide, trimethylcyclopropylammonium bromide, tetramethylammonium iodide, tetraethylammonium iodide, tetrabutylammonium iodide, tetraoctylammonium iodide, t-butylethyldimethylammonium iodide, tetradecyltrimethylammonium iodide, hexadecyltrimethylammonium iodide, octadecyaltrimethylammonium iodide, benzyltrimethylammonium iodide, benzyltriethylammonium iodide, benzyltributylammonium iodide, tetramethylammonium hydrogensulfate, tetraethylammonium hydrogensulfate, tetrabutylammonium hydrogensulfate, and the like.
As the quaternary phosphonium salt, there are, for example, tetraethylphosphonium chloride, triethylbenzylphosphonium chloride, tetrabutylphosphonium chloride, tributylmethylphosphonium chloride, tributyloctylphosphonium chloride, tributylhexadecylphosphonium chloride, tributylallylphosphonium chloride, tributylbenzylphosphonium chloride, trioctylethylphosphonium chloride, tetraphenylphosphonium chloride, tetraethylphosphonium bromide, triethylbenzylphosphonium bromide, tetrabutylphosphonium bromide, tributylmethylphosphonium bromide, tributyloctylphosphonium bromide, tributylhexadecylphosphonium bromide, tributylallylphosphonium bromide, tributylbenzylphosphonium bromide, trioctylethylphosphonium bromide, tetraphenylphosphonium bromide, tetraethylphosphoriium iodide, triethylbenzylphosphonium iodide, tetrabutylphosphonium iodide, tributylmethylphosphonium iodide, tributyloctylphosphonium iodide, tributylhexadecylphosphonium iodide, tributylallylphosphonium iodide, tributylbenzylphosphonium iodide, trioctylethylphosphonium iodide, tetraphenylphosphonium iodide, and the like.
As the sulfonium salt, there are, for example, dibutylmethylsuflonium chloride, trimetylsulfonium chloride, triethylsulfonium chloride, dibutylmethylsulfonium bromide, trimethylsulfonium bromide, triethylsulfonium bromide, dibutylmethylsulfonium iodide, trimethylsulfonium iodide, triethylsulfonium iodide, and the like.
Among these phase-transfer catalysts, iodides are preferred with a quaternary ammonium iodide being particularly preferred.
Usually, the amount of a phase-transfer catalyst to be used is within the range of about 0.001 to 0.2 mole, preferably about 0.01 to 0.1 mole per 1 mole of the allyl halide derivative (1).
Usually, the reaction temperature is within the range of 30 to 110xc2x0 C., preferably about 50 to 100xc2x0 C.
Further, addition of an inorganic salt is more preferred and examples thereof include alkali metal and alkaline earth metal halides. Specifically, sodium chloride, potassium chloride, sodium bromide, potassium bromide, calcium chloride, magnesium chloride, etc., are exemplified. The amount of such inorganic salt to be used varies depending on an amount of water as a solvent but, usually, it is within the range of about 50 to 1000% by weight, preferably about 100 to 300% by weight based on an amount of the allyl halide derivative (1).
After the reaction, the allyl sulfone derivative (3) obtained can be isolated and purified by extraction, washing, crystallization, various chromatography, and the like.
The starting compound, i.e., the ally alcohol derivative (5), can be simply and readily produced according to a method shown by the following scheme. That is, the allyl alcohol derivative (5) can be obtained by reacting the sulfone (7) and the halide (8) under basic conditions and deprotecting the protected hydroxy group of the resultant sulfone derivative (9) according to a conventional method (for example, in case of an acyl group such as R=acetyl group, etc., alkaline hydrolysis). 
The sulfone (7) can be produced by a method described in Chem. Lett., 479 (1975). Further, the halide (8) can be simply and readily obtained from isoprene by two steps according to the method described in the specification of U.S. Pat. No. 4,175,294.
Furthermore, from the allyl sulfone derivative (3), retinol can be derived according to the following scheme. That is, retinol can be simply and readily obtained by reacting the allyl sulfone derivative (3) with the halide (8), and reacting the resultant disulfone derivative (10) with a base. The allyl sulfone derivative (3) is an important intermediate for retinol useful as medicament, feed additives and food additives. 